Apparatus for transmission of messages by electricity



'(No Mo'deL) 2 Sheets-Sheet 1.

G. T. WOODS APPARATUS FOR TRANSMISSION OF MESSAGES BY ELEGTRICITY.

No 315,368. Patented Apr. 7, 1885\- (N0 ModeL) 2 SheetS Sheet 2.

G. T.'WO()DS..

APPARATUS FOR TRANSMISSION or MESSAGES BY ELEGTRICITY.

No. 315,368. S Patented Apr. 7, 1885.

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N. PETKRS. Pllolo-Lilhognpher. Waihingtun, D. I;

T UNITED STATES PATENT GRANVILLE 'r. woons, or CINCINNATI, 01110,ASSIGNOR, BY-DIREOT ND MESNE ASSIGNMENTS, TO THE AMERICAN BELL TELEPHONECOMPANY,

OF BOSTON, MASSACHUSETTS.

APPARATUS FOR TRANSMISSION O F MESSAGES BY ELECTRICITY.

SPECIFICATION forming part of Letters Patent No. 315,368, dated April 7,1885.

Application filed April 9, 1884. (No model.)

b To all whom it may concern.-

. that traverse the line-wire.

Be it known that I, GRANVILLE T. WOODS, of Cincinnati, Hamilton county,Ohio, have invented a new and useful System and Apparatus for theTransmission and Reception of Messages by Electricity, of which thefollowing is a specification. I

In the ordinary mode of sending telegraphic messages the operator uses afinger-key, whose duties are to irregularly make and break the circuit,or to vary the tension of the electric current traversing the line-wire,the ,key being operated "by the varying pressure of the operatorsfinger. This key as ordinarily constructed cannot be operated in anyother way or for any other purpose than that just mentioned. The messagethus trans mitted is received by an instrument known as a receiver orsounder, which causes audible atmospheric vibrations in response to thepulsations of the electric current traversing the line-wire. 1

It is well known that both the sender and the recipient of messages thustransmitted must be skilled operators. It is also well known that suchsounder as usually constructed will not respond to very weak electriccurrents, such as are used in telephony. My system (called by meTelegraphony) entirely overcomes the failings of the ordinary key andsounder and hasa wide range of usefulness, it being capable of use byinexperienced persons, for if, for-example, the operator cannot read orwrite the Morse signals, he has only (by means of a suitable switch) toout the battery out of the main-line circuit and out it .into a localcircuit, and then speak near the key. This having been done, the sounderat the receiving-station will cause the air to vibrate in unison withthe electric pulsations The person at the receiving-station will thusreceive the message as articulate speech.

This invention may be of great advantage in domestic use, as when twostudents are practicing the Morse alphabet they can also speak change inthe instruments. Having set forth the general advantages of Attelegraph-stations it would be of great advantage to use my system oftelegraphing,; as both oral and signal messages can be trans-. mittedand over the same line without any my invention, the same may be fullyunderstood by the following description, reference being had to theaccompanying drawings, in which Figure 1 is a rear view ofa transmitterembodying certain features of my system. Fig. 2 is a modification of thesame. Figs, 3

and 4 are axial sections. of the transmitter. shown at Figs. 1 and 2,respectively. Fig. 5 I

is a partly-sectioned side view of the receiver. Fig. 6 is an axialsection showing another form of transmitter. Fig. 7 is a general diagram including two stations.

A may represent the door of a box that con-I tains the finger-key. B isthe frame orbase of the key. 0 is the key-lever, having a button, D, onits long arm. E is a disk, dia-1 phragm, or tympauum, of soft iron orother suitable material, that carries or constitutes one electrode, thesaid lever G constituting-.01; carrying the other electrode, whichelectrode,, in the present illustration, is the button D.

F are clamps that hold the diaphragm in place upon the frame B.

I The diaphragm F, if made of metal, has its periphery incased in asoftrubber band, G. H is a circuit-breaker, hingedat h. Thiscircuit-breaker, when moved to the left, will close the circuit bystriking the stud I, which is in electrical connection with wire J. Whenthelever H, Fig. 1, is in contact with'the stud I,

the primary circuit is closed, and it is then ready for the operatoratthe distant stationto send. The lever H in its action is the same asthe circuit-closer of an ordinary telegraph-key. b

When the lever is moved toward the right, the circuit is broken, and ifthe instrument is then inclined until the ball of carbon is in contactwith the electrode on the plate E, and

also the electrode on the lever C, it will then 1 be ready for oralmessage s,- provided the switches V V, hereinafter referred to, are; Iproperly connected. 7 The frame B is electric ally connected with thewire J. The wires J and J form conductors to the respective poles of abattery, Y. The contacts (the place where the electrical communicationis varied, broken, or restored) may be of carbon or any other suitablesemi-conducting material; or they may be a combination. of some suchrefractory metal as platinum or iridium for one point,with any suitablesemi-conductorsuch as carbonfor the other point. My preferred forms andmaterials are a ball or pellet, 1, of carbon or of a refractory metal ofsuitable conductivity, which may be placed in a little cup ordepression, 2, which may be of metal or of carbon, and which isconnected to the plate E, while the other contact-point is carried bythe lever O. For some purposessuch, for example, as where it is desiredto avoid breaking of the current, (as in loud speaking)the carbon ball 1may be omitted and the platinum point be allowed to dip into mercury oracidulated water contained in said cup 2.

K K are springs, by which, in association with temper-screw L, the leverO is adjusted to give the contacts more or less play or a greater orless pressure, as the case may be. In Fig. 2 the circuit-breaker H actsindirectly, the form being that of a bell crank whose short arm Hcrosses the plate to a point under the lever 0 near its fulcrum. Aspring, K, is attached to the short arm H, and operates whennon-effeetive to press under the lever C at its fulcrum. N 0W,lf thelong arm of said crank be moved to the right, the spring K will beshifted to under a point in the long arm of the lever in front of thefulcrum, so as to force that arm upward, and thus break the circuit.A'reverse 0r retrograde movement of the crank of course, on thecontrary, permits the lever to fall, (or be depressed by thecounter-spring, as the case may be,) and to thus restore contact andclose the circuit. A modification of this device is shown in-Fig. 6,which shows two contact points or buttons, 3 4, upon a turn-bar, 5, onepoint, 3, being of platinum for telegraph use, the other point, 4, beingof carbon for telephone use. The illustration shows the device adaptedfor telephone use, the points 4 and 1 being in contact.

When shifted for service as a telegraph-key, the temper-screw L is soregulatedjas to allow predominant action of the front spring, K, so asto hold the contact-points slightly apart. In Fig. 5, M is a permanentmagnetbent so as to bring the ends near together in the form of a U.Through one limb of this magnet is screwed a soft-iron core orpole-piece, N, that extends inward, and is surrounded by two concentriccoils of insulated wire, of which coil Q, immediately around the core,is of very fine wire, preferably of the grade known as No. 36. This coilis closely envelopedin'atube, P, of soft iron,which I call the magneticsleeve, and that by a coil, Q, of coarser wire, preferably about-No. 23wire. R is a frame attached to the otherleg of the magnet. Sis a ring,of rubber or other suitable material, placed inor on both move together.

said frame first, next to whichis secured a disk-armature, T, that isfastened over the mouth of a case, U, which holds the coil and sleeve.The armature and pole-piece (core) are adjusted toward or from oneanother by screw Z, which passes through a hole in one leg of the magnetand screws into a threaded hole in the other leg of the magnet. o 0 q qare terminals of the coils O and Q, respect .ively. V V is a duplexswitch or commutator connected with the line at 0 o,with the groundlinesat '0 '1), and with the ground at g y. W is an insulating-frame thatmechanically connects, while electrically insulating, the conductors ofthe commutator, so that they will 0 indicates a transmitting-key, and Ythe batteries.

The above is a description of the more essential mechanical devices'forthe transmission and reception of messages according to mysysterm. Itnow remains briefly to explain its operation. Each station in thecircuit having been provided with both a key and a sounder, and beingconnected as hereinabove set forth, when it is desired to communicatefrom one station to another, the signals may be made by first moving thecommutator V V until V connects with point q, thus cutting out theterminal 0 of the fine coil 0, and also the ground This adjustment ofthe parts operatesto connect the battery,through coarse coil Q, with theline, as in ordinary telegraphy, and the. signals (which may be Morse orany signal agreed upon) may bemade by key in the ordinary way, andbereceived by the sounder, Fig. 5, through the coil Q. Making and breakingof the circuit alternately strengthens and weakens the core magnetism,causing the armature to be alternately attracted andcreleased, and alsocausing audible atmospheric vibrations in response to the electricpulsations sent over the line-wire. If, now, oral messages are to betransmitted, the operator at the receivingstation having been signaledthat that form of communication is desired, the operator at thetransmitting-station closes the circuit by bringing the contacts of thetransmitter-key, Figs. 3, 4, or 6, together slightly, and so adjusts thecommutator as to bringV incontact with the terminal 0, and Vin contactwith o. This brings fine coil 0 into the line-circuit and relegates thecoil Q to the local circuit. The battery-current is now local, and willtraverse the circuit from the battery Y to the key 0, thence over wire Qand through helix Q, thence over wire Q, through conductor V, andthrough ground-wires Q Q, completing circuit to battery Y, and the mainline will be traversed by transient currents induced by the momentarydisturbance of the magnetic field in the neighborhood of the helix,"when conversation begins'near the finger-keys. In an inferior form ofmy device having some useful applications the magnetic sleeve is omittedand the coarse-wire helix is directly around the fine-wire helix.

o ndv I claim as new and of my invention- 1. In combination with andforming a part of a system for electric transmission of messages, a keyfor varying or breaking an electric current, having contacts 1 D,respectively composed of carbon and a refractory metal, arranged andoperating as set forth.

2. In a system for electrical transmission of messages, a sounder havinga helix of high resistance in the line-circuit, surrounded by a helix oflow resistance in circuit with the transmitter and local battery, theline being connected to a switch which is adapted to out which inventionI hereunto 2o GRANVILLE T. WOODS.

Attest:

G120. H. KNIGHT, S. S. CARPENTER:

